The present invention relates to treatment of organs. In particular, the present invention relates to treatment of organs that have been subjected to trauma or ischemia.
When an organ has been injured or its blood supply compromised, timeliness of treatment can be critical. Organ tissue necrosis, or death, begins when the organ""s blood supply is compromised and treatment is ineffective with respect to organ tissue that has died prior to treatment. Nevertheless, the time required for proper diagnosis and treatment of the organ cannot be eliminated.
The brain is no exception. Injury to the brain may result from increased pressure due to swelling of brain tissue. For example, swelling may result from internal bleeding such as from a ruptured aneurysm. Alternatively, generalized head trauma may cause swelling of brain tissue. Injury to the brain may also be the result of a lack of oxygen to brain tissue due to an embolus present within a cerebral vessel. Such an embolus can cut off an adequate blood supply to portions of brain tissue. As noted in these examples, perfusion of brain cells is compromised in both trauma and ischemia.
When brain tissue is subjected to such traumas noted above the effects as well as the need for treatment are immediate. The rate at which brain tissue dies is dependant on several factors, such as the degree of swelling or, in the case of cerebral embolism, the presence or absence of collateral vessels supplying alternative avenues of perfusion.
Treatment of the injured brain first requires a proper diagnosis. A diagnosis pinpointing the originating site of the injury can come from a computed tomography (CT) scan. From a logistical standpoint, a patient that presents, for example at an Emergency Room, with a head trauma will not likely obtain CT scan results in less than half an hour. During this critical time, brain tissue continues to die as a result of the head trauma.
Once diagnosed, the treatment chosen will take a significant amount of additional time to carry out. For example, if the brain has been subjected to an ischemic stroke, drugs such as Tissue Plasminogen Activator (TPA) may be given to the patient to help dissolve any thrombus or blood clot. Alternatively, if swelling is of concern, a hole may need to be drilled through the skull to relieve pressure on brain tissue. Additionally, more direct vascular intervention may be required. In such cases a host of catheter lab procedures may be employed. In more extreme cases, actual brain surgery may be required.
Regardless of the treatment path chosen, several hours will likely be lost during the course of the treatment. Throughout this time brain tissue will continue to die. The problem is compounded by the fact that the brain tissue cannot be regenerated.
In order to combat the problem of brain tissue death attempts have been made to curb the rate of brain tissue death. As noted above, the rate of brain tissue death is affected by factors such as the degree of swelling involved, or the overall lack of oxygen supplied to the affected tissue. Therefore, attempts to curb the rate of brain tissue death have focused on the induction of hypothermia in the patient. Hypothermia can reduce swelling. Tissue affected by hypothermia will also experience a decrease in metabolic requirements, and thus, experience a decrease in need for oxygen.
Hypothermia can be induced to reduce the core temperature of a patient. That is, the temperature of the entire body of the patient can be reduced. This can be done by reducing the temperature of the patient""s blood. Reducing even a portion of the patient""s blood will result in a generalized cooling of the body as the blood is carried throughout the body of the patient. However, in the case of a head trauma, a generalized reduction in the core temperature of the patient is limited in effectiveness. Reduction of a body""s core temperature means that hypothermia will not be focused on the brain tissue specifically. Rather, the temperature of the brain tissue, as in the rest of the body, will be reduced by a small amount. Even if the blood of the brain is cooled directly, the focus of this cooling effect will be lost as this cooled blood, along with the remainder of the patient""s blood (e.g. about 5 liters), is circulated throughout the body. In the end, a generalized core temperature reduction is the major effect obtained. This problem is applicable to any organ for which hypothermia is to be induced. Therefore, what is needed is an improved method of cooling an organ.
In one method of cooling an organ a portion of a body fluid bathing the organ is withdrawn. A cool fluid is infused during the withdrawing.
In yet another method of cooling an organ a volume of up to about 5% of a body fluid bathing the organ is withdrawn. A cool fluid is infused.
Another embodiment of a catheter is provided with an inlet port to withdraw a portion of a body fluid bathing an organ from a location adjacent the organ. An outlet port is included to infuse a cool fluid to the location as the portion of the body fluid is withdrawn.
An embodiment of an organ cooling assembly is provided including a pump assembly and a catheter coupled to the pump assembly. The catheter includes an inlet port and an outlet port. The pump is to withdraw a portion of a body fluid bathing an organ through the inlet port and to infuse a cool fluid through said outlet port.